How much coffee is really okay?

Well since I do 12 cups a day, I fall between these two points.  And you don't even mention the main reason for coffee.

My reasons for coffee are here: No clue on how much I need for these preventions so I'm not taking any chances on falling short. 

How coffee protects against Parkinson’s Aug. 2014 

 Coffee May Lower Your Risk of Dementia Feb. 2013 

And this: Coffee's Phenylindanes Fight Alzheimer's Plaque  

This also: Two Compounds in Coffee May Team Up to Fight Parkinson's  

If your stroke hospital doesn't have a 24 hour coffee station they are completely incompetent. Not doing so should be a fireable offense for the stroke hospital president.

How much coffee is really okay?

There is a lot of conflicting research out there about how much coffee is too much, and whether coffee is good or bad for your health. For example, a study conducted by researchers at Queen Mary University of London, United Kingdom suggested that drinking up to 25 cups of coffee per day is safe for heart health. However, another study in The American Journal of Clinical Nutrition suggested that drinking more than six cups of coffee per day is associated with a moderate increase in the risk of cardiovascular disease.(I will take that risk for dementia prevention.)
“Coffee intake research is conflicting,” said Dr. Conway. “Although some research suggests that too much coffee can be harmful, other studies suggest that drinking coffee could lower the risk of developing certain health conditions, such as heart disease.”
Drs. Conway, Florio, and Ukabi said that they advise most patients to drink coffee in moderation. However, patients with certain health conditions may need to be aware of how coffee affects their body.
For example, Dr. Ukabi said that if you experience heart palpitations after drinking coffee, you should talk to your doctor—you may be drinking too much.
“I usually only talk to patients about caffeine intake if it might be related to another health condition, such as bladder irritation, heart disease, or insomnia,” said Dr. Florio. “In general, two-to-four eight-ounce cups of coffee per day are a normal, healthy amount for people who do not have an underlying health condition.”
Also, Dr. Florio said it’s important to know what researchers consider to be a “cup” of coffee.
“What you buy in the store is usually much more than one cup. It’s also important to know how much caffeine is in the coffee, as different types of coffee have varying amounts of caffeine,” said Dr. Florio.
WCMG physicians also advise patients to be conscious of what they are adding to their coffee and the effect it may have on calorie intake.
“Black coffee is best because you can avoid added calories and sugar from cream and sweeteners,” said Dr. Ukabi.
Bottom line: A few cups of coffee per day are safe for most people who do not have other health conditions. However, you should pay attention to the amount of caffeine the coffee contains and the size of the coffee—as well as how drinking coffee affects your body—to make sure you aren’t drinking too much. You should also be aware of how added sweeteners or cream may impact your calorie intake.